Alterations in the immune phenotype of thymectomized children and the development of atopic disorders after heart transplantation
Abstract
Background
Atopic disorders are more common in children after heart transplant (HTx). We hypothesized that HTx at an early age and thymus excision (TE) affect development of T and B cells, especially regulatory T cells (Tregs), which help maintain tolerance.
Methods
In this single-center study including 24 patients transplanted between 2013 and 2018, we investigated lymphocyte patterns in relation to these factors using flow cytometry. Clinical data were collected from standardized questionnaires and medical charts. Patients were stratified into TE and non-TE groups as well as patients with and without post-transplant atopy development/worsening.
Results
64% of TE patients experienced new or worsening asthma/eczema post-transplant compared to 20% of non-TE patients. TE patients had higher total Treg proportions (CD4+CD25+CD127lo) than non-TE patients (p = .043), but borderline significantly lower naïve Tregs (CD45RA+CD27−) (p = .057). Memory CD4+ T cells were higher in TE patients in trend (p = .084). Total Tregs did not differ between atopic/nonatopic groups, although naïve Tregs were significantly lower in atopic patients (p = .028). Memory CD4+ T cells were higher in atopic patients in trend (p = .082). IgM+IgD+ B cells were higher in nonatopic patients in trend (p = .064).
Conclusions
New/worsening atopy is more common in thymectomized HTx children and is associated with alterations in T-cell profiles. Avoiding TE may prevent these alterations and reduce incidence of atopy post-HTx.
CONFLICT OF INTEREST
Tiffany Kim reports summer studentship funding from Alberta Innovates Health Solutions and the Alberta Transplant Institute, during the conduct of the study. Dr. Simon Urschel reports a joint seed grant of the University of Alberta, Faculty of Medicine and Dentistry and the Women, and Children's Health Research Institute, Alberta, Canada, during the conduct of the study. Dr. Lavinia Ionescu, Dr. Nicholas Avdimiretz, Faye Murdoch, Ingrid M. Larsen, Dr. Bruce Motyka, and Dr. Lori J. West do not have any conflicts of interest to disclose.
Open Research
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the corresponding authors if necessary, upon request.
